Cis-5-hydroxy-L-pipecolic acid is a kind of modified amino acid, which has a structure consisting of L-pipecolic acid introduced with hydroxyl group, and it is a substance useful as a synthetic intermediate material of drugs.
Biological methods for producing L-pipecolic acid (or 2-piperidinecarboxylic acid or L-homoproline) have already been reported (Non-patent documents 1, 2, and Patent document 1). In these reports, L-pipecolic acid is produced from L-lysine by using Escherichia coli having the following polynucleotides (also referred to as DNAs).    a) A polynucleotide encoding a protein having the L-lysine 6-aminotransferase enzyme activity    b) A polynucleotide encoding a protein having the pyrroline-5-carboxylate reductase enzyme activity
In these reports, the lat gene (SEQ ID NO: 1) derived from Flavobacterium lutescens IFO3084 strain is mentioned as an example of the polynucleotide of a) mentioned above, and the proC gene (SEQ ID NO: 3) derived from Escherichia coli is mentioned as an example of the polynucleotide of h) mentioned above. Since Escherichia coli originally has the proC gene, an Escherichia coli strain introduced with the lat gene and able to express it has an L-pipecolic acid-producing ability. Further, there have also been reported that the production rate of L-pipecolic acid was improved in Escherichia coli also having a DNA encoding a protein having the lysine-specific permease activity, for example, the lysP gene derived from Escherichia coli (SEQ ID NO: 4).
It has been reported that the CAC47686 protein derived from the alfalfa leguminous bacterium, Sinorhizobium meliloti 1021, has an ability to convert L-pipecolic acid into cis-5-hydroxy-L-pipecolic acid (Non-patent document 3). The amino acid sequence of this protein is registered at the database GenBank with an accession number of CAC47686. The nucleotide sequence encoding it is registered at the database GenBank with an accession number of AL591792 (SEQ ID NO: 6).
It has also been reported that the BAB52605 protein or CAC47686 protein derived from the Lotus corniculatus var. japonicus leguminous bacterium, Mesorhizobium loti MAFF303099, has an ability to convert L-proline into cis-4-hydroxyproline (Patent document 2). The amino acid sequence of the BAB52605 protein is registered at the database GenBank with an accession number of BAB52605. The nucleotide sequence encoding it is registered at the database GenBank with an accession number of BA000012 (SEQ ID NO: 7, loti gene).